This invention relates to a main contact blade assembly for a switching device, and more particularly, to an apparatus for spacing and separating a plurality of circuit breaker contact blades.
When the current carrying contacts of a circuit interrupting device are separated while a current is flowing through the contacts, an arc is normally formed between the contacts. Depending on the intensity and duration of the arc, the contact material and materials surrounding the arc experience varying degrees of deterioration. For example, the contact surfaces can be eroded such that the contact interface has an increased resistance which causes localized heating and further deterioration of the contacts. In dealing with this problem, it is desirable to either extinguish the arc in the least amount of time possible and/or move the arc from between the contacts to a location where the damage done by the arc does not severely affect the operation of the circuit interrupting device.
Additionally, it is important to keep the contact carrying blades of a circuit breaker separated and consistently spaced while also insulating the individual contact blades. One way of insulating the individual contact blades is to coat each blade with an insulating material. During the opening of an electrical device under fault conditions, various electromagnetic forces act on the components of a circuit breaker. In particular, the parallel current paths in the contact blades tend to produce electromagnetic forces which urge the contact blades together. One method for preventing the contact blades from being urged together is to insert individual spacers between the contact blades.
Accordingly, it is important to provide means for separating the contact blades. Additionally, it is important to provide means for extinguishing and/or moving an arc to a location where damage done by the arc is not critical.